Combination changing cylinder lock

ABSTRACT

A cylinder lock is disclosed having tumbler pins comprising a plurality of interlocking segments, the interfaces of adjacent pairs of segments being such that the adjacent segments may be placed in shear, locking, or passover orientations dependent upon their relative rotations. To change the combination of the service key, a master key is used to place each pair of adjacent pin segments in the shear orientation. A service key having the desired new combination is then used to operate the lock and the adjacent pin segment pairs are selectively placed in the locking or passover orientations depending upon the requirements of the new combination.

United States Patent [191 Burlingame Oct. 7, 1975 COMBINATION CHANGING CYLINDER Primary Examiner-Robert L. Wolfe LOCK Attorney, Agent, or FirmNeuman, Williams, [76] lnventor: Glen E. Burlingame, 2858 w. 55th Anderson and St., Chicago, [11. 60632 22 Filed: Mar. 1, 1974 [57] ABSTRACT [21] App]. No: 447,272 A cylinder lock is disclosed having tumbler pins comprising a plurality of interlocking segments, the interfaces of adjacent pairs of segments being such that the [52] US. Cl 70/383; 70/378 adjacent segments may be placed in shear, locking, or t. Cl. E05B /14; EOSB /00 passover orientations dependent upon their relative Field Of Search 364 A, rotations. To change the combination of the service 70/373, 3 385 key, a master key is used to place each pair of adja- V cent pin segments in the shear orientation. A service [56] References Cited key having the desired new combination is then used UNITED STATES PATENTS to operate the lock and the adjacent pin segment pairs 1,590,232 6/1926 Freman 70/383 are selectivdy Placed in the Ocking or Pass)ver Orien- 2,111,098 3 1938 Segal 70/378 x tations depending p the requirements of the new 3,427,814 9/1947 Schachinger 70/383 m a 3,722,240 3/1973 Spain 70/364 A 4 Claims, 15 Drawing Figures 20.... q 26 /I k \l 7 M II I w 1 l 1 54 I 1 22 58 I\ K l 1 l4) l l l n 52 L g a Q l i 1 l I l 56 I I l1 Gk i y g I ll i s 4i: \Y l 64 Sheet 1 of 3 3,910,083

US. Patent 0a. 7,1975

Sheet 2 0f 3 US. Patent Oct. 7,1975

-U.S. Patent 0a. 7,1975 Sheet 3 of3 3,910,083

COMBINATION CHANGING CYLINDER LOCK BACKGROUND OF THE INVENTION This invention relates to pin tumbler cylinder locks in which the combination of the service key can be changed externally without access to the lock interior. Combination changing cylinder locks are, of course, well known to the art. Examples of such locks are shown in US. Pat. Nos. 988,663, 1,004,904, 1,917,302, 2,113,007, and 2,427,814. Each of the listed patents except the third shows pin tumbler cylinder locks wherein the combination of the service key may be changed by either including or excluding a vari able number of tumbler pin segments from each tumbler pin.

The combination pin tumbler cylinder locks of the past have, however, been characterized by a number of disadvantages. A primary disadvantage has been the excessive size and bulk of the combination changing locks to the prior art. In particular, such locks have been considerably larger than the standard, more conventional fixed combination lock. This excess size meant that prior combination changing locks could not be simply substituted for previously existing fixed combination locks. It also meant that prior combination changing locks could not be used with conventional latching hardware intended for use with fixed combination locks.

Prior combination changing locks were also excessively expensive and thus, despite their advantages over fixed combination locks, have not found wide acceptance in the market place. Moreover, it was often relatively difficult to alter the service key combination of combination changing locks of the prior art and either a great amount of time or skill was required to effect the desiredchange. However, it is also undesirable for the combination of a lock to be so easily changed that the combination may be altered either unintentionally or by unauthorized persons. It should be noted, of course, that the combination of conventional fixed combination cylinder locks can also be altered but the operation must usually be performed by a locksmith and requires removal of the lock. Finally, many combination changing cylinder locks of the past have used keys with unusual configurations. This has often been a disadvantage because it meant that the keys could not be duplicated readily.

SUMMARY OF THE INVENTION There are provided by this invention combination changing pin tumbler cylinder locks wherein the tumblers are comprised of a plurality of interlocking pin tumbler segments. The engagement characteristics of adjacent pairs of pin tumbler segments may be changed at least between a locking configuration and a passing configuration. To change the lock combination, means are provided to first neutralize the previously existing combination and place all the adjacent pairs of interlocking pin segments in a passing orientation. To set the new combination, selected pairs of adjacent inter locking pin segments are placed in the locking orientation. A master key may be provided which may also be used in the neutralizing operation.

It is, thus, an object of this invention to provide a combination changing pin tumbler cylinder lock which has approximately the same physical dimensions as a conventional, fixed combination pin cylinder lock.

It is an object of this invention to provide a combination pin tumbler cylinder lock which may be used interchangeably with many fixed combination pin tumbler cylinder locks already in service.

It is an object of this invention to provide a combination changing pin tumbler cylinder lock which is relatively inexpensive to manufacture.

It is an object of this invention to provide a combination changing pin tumbler cylinder lock wherein the combination may easily be changed by authorized persons but yet contains adequate safeguards against accidental change or change by unauthorized persons.

It is an object of this invention to provide a combination changing pin tumbler cylinder lock using keys which may be readily duplicated.

Further objects and advantages of this invention will be apparent from this specification, the appended claims, and the drawing.

DESCRIPTION OF THE DRAWING FIG. 1 is a cutaway, sectional view partly in schematic form for clarity of exposition showing a combination changing cylinder lock of this invention;

FIG. 2 illustrates two locking pin tumbler segments of the lock of FIG. I in a nonnested configuration;

FIG. 3 illustrates two locking pin tumbler segments of the lock of FIG. 1 in a nested configuration;

FIG. 4 illustrates two locking pin tumbler segments with an intermediate master pin tumbler segment of the lock of FIG. 1;

FIG. 5 illustrates a portion of the lock cylinder of the lock of FIG. 1;

FIG. 6 is a cutaway view of a portion of the lock of FIG. 1 to illustrate the operation of the master key;

FIG. 7 shows a portion of the lock cylinder and associated components of the lock of FIG. I to illustrate the operation of the upper pin tumbler segment rotating bar;

FIG. 8 is similar to FIG. 7 for further illustrating the operation of the upper pin tumbler segment rotating bar;

FIG. 9 shows a portion of the lock body and associated components of the lock of FIG. 1 to illustrate the operation of the lower pin tumbler segment rotating bar.

FIGS. 10-13 are cutaway views of the lock cylinder and associated components for actuating the upper and lower pin tumbler segment rotating bars in the lock of FIG. I;

FIG. 14 is a section view illustrating the interaction of the pin tumbler segment rotating bars and the lock- ,ing pin tumbler segments of the lock of FIG. 1; and

FIG. 15 is a detail view of the upper locking pin tumbler segment rotating bar pin.

DESCRIPTION OF THE PREFERRED EMBODIMENT A combination changing pin tumbler cylinder lock of this invention is disclosed in this specification and the appended drawings. It will be obvious to those skilled in the art that this invention may be used in many forms other than that of the disclosed embodiment.

The lock 10 of the drawing includes a lock body 12 of generally cylindrical shape having a cylinder bore 14 also of generally cylindrical shape with its axis parallel to that of lock body 12. A lock cylinder 16 is disposed within cylinder bore 14. The body 12 includes four body tumbler bores 18. Each body tumbler bore 18 is generally cylindrical, has an axis perpendicular to the axis of cylinder bore 14, and is open at the lower end as shown in FIG. 1 and in communication with cylinder bore 14. In the lock of FIG. 1 the axes of the four tumbler bores 18 lie in common plane also including the axis of cylinder bore 14. The lock cylinder 16 includes four correspondingly located cylinder pin tumbler bores 20 although only the rearward two are shown in FIG. 1. Cylinder pin tumbler bores 20 are also generally cylindrical and their axes coincide with the axes of body pin tumbler bores 18. The lock cylinder 16 also includes an elongated keyway 22 for receiving a key 23 and running generally parallel to the axis of lock cylinder 16. The keyway 22 is in communication with cylinder pin tumbler bores 20 at the lower end of those bores as shown in FIG. 1. The rearward face of lock cylinder 16 includes four bores 24 for receiving a latching arm 25 which connects the lock to an associated latching or bolt mechanism, not shown. A leaf spring 27 is suspended in cylinder 16 at the end of keyway 22 for performing a function which will be explained subsequently.

Each of the body pin tumbler bores 18 and corresponding cylinder pin tumbler bores 20 jointly receive a pin tumbler 26, only the rearward two pin tumblers being shown in FIG. 1. Each of the cylinder bores 18 receives a spiral spring 28 having a generally conical shape disposed between the top of the bore and the pin tumbler 26, again only the rearward two springs 28 being shown in FIG. 1. Springs 28 resiliently urge tumbler pins 26 downward as shown in FIG. 1 toward the bottom of the keyway 22. When a key 22 is inserted in keyway 22 as shown in FIG. 1, the tumbler pins are lifted upward in the tumbler bores 18 and 20 against the force of springs 28.

Each pin tumbler 26 is comprised of a plurality of locking pin tumbler segments 30, as are perhaps best shown in FIGS. l4. Locking pin tumbler segments 30 are of a generally cylindrical, wafer configuration but the lower surface thereof includes a raised, tongue structure 32 and the upper surface includes a depressed groove structure 34. The tongues 32 and grooves 34 are such that when adjacent locking pin tumbler segments are properly oriented within the tumbler bores so that the axes of the tongue structures lie in the same plane, the segments nest within one another as shown in FIG. 3. Each of the locking pin tumbler segments 30 also includes a lug 36 alligned with the tongues 32 and grooves 34 and projecting from the sides thereof. In FIG. 1, the most rearward tumbler 26 is shown without lugs 36 for ease of understanding while the next forward tumbler 26 is shown with lugs 36. The upper and lower surfaces of locking pin tumbler segments 30 including the generally horizontal surfaces of tongues 32 and grooves 34 have a spherical or dome shape with the same radius of curvature as that of lock cylinder 16. The center of curvature of these surfaces coincides with the intersection of the axis of cylinder 16 and the axis of the corresponding cylinder pin tumbler bore 20 when the respective surface is alligned with the surface of cylinder 16.

The pin tumblers 26 also include bottom pin tumbler locking segments 38 which are similar to locking pin segments 32 except the bottom surface as shown in FIG. 1 is dome-shaped so that it may follow the undulations of a key as the key is inserted into keyway 22. The

top pin tumbler locking segment of each pin tumbler 26 has a flat top surface. Each pin tumbler also includes a master pin tumbler segment 40 disposed between two other pin tumbler segments; its upper and lower surfaces do not include the tongue and groove structures of locking segments 30 but are curved just as are the surfaces of segments 32. Master pin tumbler segments 40 have a thickness approximately equal to the height of a tongue 32 on locking segments 30. The surfaces of locking pin tumbler segments 30 in contact with master segment 40 do not include a tongue or groove structure. Master pin tumbler segments permit operation of a master key, as will subsequently be explained.

In addition to the body pin tumbler bores 18, lock body 12 also includes an elongated channel 42 disposed parallel to the axis of lock body 12 approximately tangentially to tumbler bores 18 as is best shown in FIG. 14. An opening 44 is provided between each tumbler bore 18 and channel 42 for receiving lugs 36 of the pin tumbler segments. Opening 44 is sufficiently wide that the tumbler pin segments may rotate approximately 45 about the axis of bore 18. An upper tumbler pin segment rotating bar 48 is disposed within channel 42 and extends over approximately the entire length of lock body 12. At positions adjacent each bore 18 upper pin tumbler segment rotating bar 48 includes notches 50 into which lugs 36 project. Notches 50 extend the entire height of the rotating bar 48. A sleeve 52 is located at the rearward end of rotating bar 48 and includes therein a pin 54. A helical spring 56 resiliently urges pin 54 in a downward direction as shown in FIG. 1.

Lock cylinder 16 includes an elongated channel disposed parallel to the axis of cylinder 16 approximately tangentially to tumbler bores 20 with openings provided between each tumbler bore and the channel for receiving lugs 36 and permitting rotation of the pin tumbler segments by approximately 45. Thus, a cross section of cylinder 16 will have the same appearance as that of FIG. 14 discussed with respect to the lock body 12. A lower pin tumbler segment rotating bar 56 is disposed within the channel in lock cylinder 16 and extends over approximately the entire length of lock cylinder 16. At positions adjacent each bore 20 lower pin tumbler segment rotating bar 56 includes notches 58 extending its entire height into which lugs 36 project. A sleeve 60 is located at the rearward end of rotating bar 56 and includes therein a pin 62. Pin 62 is resiliently urged downwardly as shown in FIG. 1 by a helical spring 64. At the lower end thereof sleeve 60 includes a cutout portion 66 which exposes a cam surface 68 cut into pin 62.

Pin 62 extends down into keyway 22 and has a length approximately equal to the diameter of cylinder 16. An undulating groove 69 having a shape which is best shown in FIG. 8 is disposed on the surface of cylinder bore 14 in lock body 12. When pin 62 is displaced upwards against spring 64 as is shown in FIG. 1, or downwards is shown in FIG. 8, it projects into groove 69. As cylinder 12 is rotated within the lock body by rotation of the key, lower pin tumbler segment rotating bar 56 is then caused to move back and forth with respect to cylinder 12 in accord with the undulations in groove 69. Pin 62 also includes adjacent the upper end thereof a collar 70 as is best shown in FIGS. 10-13. An insert 72, also best shown in FIGS. l013, is in fixed relationship to lock body 12 and extends over approximately the upper left hand quadrant of the circumference of lock cylinder 16 immediately adjacent pin 62. It is such that if pin 62 is displaced against the force of spring 64 while the pin 62 is horizontal and the cylinder is then turned slightly clockwise, the interaction of collar 70 and insert 72 will maintain pin 62 in its displaced position until the cylinder is rotated back counterclockwise sufficiently to bring the collar off the insert.

There is also included within lock cylinder 16 an undulating groove 74 for engagement with pin 54 when pin 54 is forced into engagement with groove 74 by spring 56. Groove 74 is best shown in FIG. 8. Groove 74 is provided with a wide segment 75 at the upper extremity thereof. In the portion of groove 74 displaced from segment 75, ledges 77 cover the side portions as is shown in FIG. 15. Pin 54 includes a groove 79 about the circumference thereof to provide clearance for ledges 77 as the pin traverses groove 74. A shoe 76 is provided in a cavity 78 lying immediately below groove 74. Both shoe 76 and cavity 78 must take the same shape as the groove 74 over segment 75 thereof. A bore 80 through lock cylinder 16 permits a pin 82 extending from shoe 76 to engage cam surface 68 on pin 62. When pin 62 is in its lower position as shown in FIG. 1, shoe 76 rides up against pin 54 preventing it from engaging groove 74. When pin 62 is displaced against the force of spring 56 acting through pin 54 against the shoe 76 so that pin 76 is lowered into cavity 78 and both pin 54 and the upper pin tumbler segment rotating bar 48 follow the undulations of groove 74 as the cylinder is rotated with respect to the lock body. Shoe 76 and ledges 77 prevent pin 54 from falling into groove 74 except when shoe 76 is lowered.

The operation of the lock as thus far described will now be described. Any pair of adjacent locking pin segments in the same tumbler are capable of engaging in three different mannersdepending upon their relative rotations. As shown in FIG. 3, if two of the adjacent locking segments are nested together and it is attempted to impart relative rotation to them in the direction of the arrows labelled A, Le, parallel to the axis of the tongue and groove structures, the two segments will easily part from one another. This may be termed the shear orientation. If, however, the two adjacent locking segments are nested together and it is attempted to impart relative motion to them in the direction of the arrows labelled B, i.e., in a direction other than parallel to the axis of the tongue and groove structures, the segments will not part from each other if they are not permitted to be vertically displaced. This may be termed the locking orientation. As is shown in FIG. 2, if two of the adjacent locking segments are not nested together, they may easily pass over each other without the opposing tongue and groove structures intermeshing. This may be termed the passover orientation. It will be observed that the adjacent segments may be rotated past one another in both the, shear and the passover orientations, so both these orientations can be referred to as passing orientations. The basic purpose of the described lock mechanism is to arrange the individual pin segments of each tumbler so that only the desired keys will operate the lock.

The operation of the lock will be explained with reference to the procedure for changing the combination. A master key is first inserted into the lock. It differs from a conventional or service key for the lock in at least two respects. First, as shown in FIG. 6 it includes an extended tip 84 which when the key is fully inserted into the lock against the force of spring 27 will raise pin 62 against the force of spring 64. The service keys do not include tip 84. Second, the configuration of the master key is in successive plateaus, one plateau corresponding to each pin tumbler 26. The width of each plateau or level must be sufficiently wide that the master key may travel a sufficient distance on the keyway 22 to raise pin 62 on tip 84' without causing any displacement of the pin tumbler segments in a direction parallel to their axes. The required width of the plateaus is indicated by dimension lines C in FIG. 6.

The interface between lock body 12 and lock cylinder 16 forms a shear plane where relative shearing motion occurs. The master pin tumbler segments 40 are disposed in each tumbler so that when the master key is inserted into the lock, either the upper or lower surface of the master pin tumbler segment 40 for each tumbler is brought to the shear plane. For any individual pin tumbler, if the previously set service key combination included the passover orientation of adjacent locking segments below the master segment, the lower master segment surface would be brought to the shear plane; if the previously set service key combination in cluded the passover orientation above the master segment, the lower master segment surface would be brought to the shear plane. Since no locking surfaces of the pin tumbler segments are present at the shear plane after insertion of the master key, the key and cylinder may be freely turned.

When the master key is simply inserted into the lock, pin 62 is at the position shown in FIG. 13. To change the combination, the key is rotated 90". counterclockwise so that pin 62 is in the position of FIG. 12. The master key is then pushed into the keyway against the force of spring 27 so that tip 84 displaces pin 62 as shown in FIG. 10 and moves collar outwardly so that it clears insert 72 and pin 62 engages groove 68 in the body. Shoe 76 is also moved inwardly so that pin 54 engages groove 74 in the cylinder. The master key is then rotated back clockwise in the direction of the arrow shown in FIG. 8, so that pin 62 has the position of FIG. 11, and then withdrawn from the keyway. Pin 62 remains in the displaced position shown in FIG. 11 because of the interaction of collar 70 and insert 72.

During the rotation of the master key to return it to its original position, upper pin tumbler segment rotating bar 48 follows the undulation of groove 74. That groove is such that with reference to FIG. 14, the rotating bar 48 will be moved from the central position there shown sufficiently far to the right that the left side of -notch 50 will engage each of the lugs 36 of the locking pin tumbler segments which had previously been displaced to the left and move them to the right. The rotating bar 48 will then be moved back past the central position and sufficiently far to the left that all the lugs 36, both those that were displaced by the previously mentioned rightward movement of the bar 48, will be engaged by the right side of notch 50 and returned to the central position shown by the dashed line in FIG. 14. The pattern of motion of rotating bar 48 may be visualized as being two units to the right and three units to the left. A similar action takes place with respect to lower pin tumbler segment rotating bar 56 except that, with reference to FIG. 14, it. is first moved from the central position shown to the left and then back to the right past the central position. The pattern of motion of rotating bar 56 may then be visualized as being two units to the left and three units to the right.

A service key having the desired new combination is then inserted into the keyway, the tumblers following the pattern of that key, and the cylinder is rotated counterclockwise 90 to the position of FIG. 10. The upper and lower rotating bars 48 and 56 then move in the reverse of the pattern just described, i.e., bar 48 moves three units to the right and two units to the left and bar 56 moves three units to the left and two units to the right. It will thus be seen that rotation of the service key causes all locking pin tumbler segments in the lock body to be rotated counterclockwise as shown in FIG. 14 so that their lugs are displaced to the right and all locking pin tumbler segments in the lock cylinder to be rotated clockwise so that their lugs are displaced to the left. Thus, all the segments above the shear plane are put in locking orientations relative to one another, and the two segments immediately adjacent either side of the shear plane are placed in the passover orientation. The lock can then be opened only by keys having the configuration of the service key used to set the lock or a master key.

It should be noted that when two adjacent locking pin segments on either side of the shear plane are in the shear orientation, they cannot be rotated relative to one another. Therefore, lock cylinder 16 must be rotated sufficiently to substantially disengage the segments on the opposite sides of the shear plane before movement of the rotating bars 48 and 56 is commenced. This may be achieved by including an initial, relatively straight portion in grooves 68 and 74 which essentially lies in a plane perpendicular to the axis of the lock cylinder. These portions are indicated by numbers 75 and 88 in FIG. 8. It should also be noted that when locking pin tumbler segments 32 are disposed on either side of the shear plane, the tongue 32 will extend below the surface of lock cylinder 16 and prevent rotation thereof unless a groove 86 is provided therein adjacent bore 20. The groove should have a depth at least equal to the height of the tongues 32 immediately adjacent the bore but may decrease in depth with distance away from the bore as the pin tumbler segments above the shear plane may rise up in bore 18 against the force of springs 28. The groove 86 should also flare out or widen as it departs from bore 20 to permit rotation of the pin tumbler segments as the cylinder 16 rotates. No specific means is shown in the drawing for maintaining the pin tumbler segment rotating bars 48 and 56 in a fixed position during normal operation of the lock. This may be achieved by placing a ball bearing within a bore in the side of the channels containing the rotating bars in body 12 and cylinder 16 and spring loading it for displacement into a correspondingly located dimple on one of the sides of rotating bars 48 and 56, respectively, which is generally parallel to the axis of the lock body 12.

It will thus be seen that a combination changing pin tumbler cylinder lock has been provided which fulfills each of the above-mentioned objects, It will be apparent that many modifications can be made to the lock shown without departing from the spirit and scope of this invention. For example, the surfaces of the pin tumbler segments are subject to variation. Many different mechanisms may be provided for achieving rotation of the pin tumbler segments.

I claim:

l. A key operated tumbler lock including provisions for changing the configuration of the service key usable to operate the lock and comprising:

a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bores;

a lock cylinder disposed for rotational motion within said cylinder bore and including a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores;

a plurality of pin tumblers disposed in said lock body pin tumbler bores and said lock cylinder pin tumbler bores, at least one of said pin tumblers comprising a plurality of adjacent pin tumbler segments having adjacent surfaces with variable engagement characteristics dependent upon the relative orientation of said pin tumbler segments and changeable between at least a locking configuration and a passing configuration;

means for placing said pin tumbler segments in said passing configuration to enable changing the configuration of the service key; and

means for placing selected ones of said pin tumbler segments in said locking configuration to effect a change in the configuration of said service key.

2. A key operated tumbler lock including provisions for changing the configuration of the service key and comprising:

a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bore;

a lock cylinder disposed for rotational motion within said cylinder bore and including a keyway and a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores;

a plurality of pin tumblers disposed in said lock body pin tumbler bores and said lock cylinder pin tumbler bores, at least one of said pin tumblers comprising first and second adjacent pin tumbler segments, the adjacent surfaces of said first and second pin tumbler segments having variable engagement characteristics dependent upon the relative orientation of said first and second pin tumbler segments and changeable between at least a locking orientation and a passing orientation;

means for placing said first and second pin tumbler segments in said passing orientation to enable changing the configuration of the service key; and

means for selectively placing said first and second pin tumbler segments in said locking orientation to effect a change in the configuration of said service key.

3, A key operated tumbler lock including provisions for changing the combination of the service key and comprising: 4

a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bore;

a lock cylinder disposed for rotational movement within said cylinder bore and including a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores;

a plurality of pin tumblers disposed in said pin tumbler bores, each pin tumbler comprising a plurality of adjacent locking pin tumbler segments, the interfacing surfaces of each adjacent pair of said locking pin tumbler segments having variable engagement characteristics dependent upon the relative orientation of the ones of said pair of adjacent locking pin tumbler segments and changeable between a locking orientation, a passover orientation, and a shear orientation;

neutralizing means for orienting said locking pin tumbler segments so that each adjacent pair of said locking pin tumbler segments is in said shear orientation to enable changing the combination of the service key; and

setting means for orienting said locking pin tumbler segments so that selected ones of said adjacent pairs of locking pin tumbler segments are in the locking orientation and other selected ones of said adjacent pairs of locking pin tumbler segments are in the passover orientation to effect a setting of the combination of said service key.

4. A key operated tumbler lock including provisions for changing the combination of the service key and comprising:

a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bore;

a lock cylinder disposed for rotational movement within said cylinder bore: and including a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores;

a plurality of pin tumblers disposed in said pin tumbler bores, each pin tumbler comprising a plurality of adjacent locking pin tumbler segments, the interfacing surfaces of each adjacent pair of said locking pin tumbler segments having variable engagement characteristics dependent upon the relative orientation of the ones of said pair of adjacent locking pin tumbler segments and changeable between at least a locking orientation and a passing orientation; and

means for orienting said locking pin tumbler segments so that selected ones of said adjacent pairs of locking pin tumbler segments are in the locking orientation and other selected ones of said adjacent pairs of locking pin tumbler segments as in the passing orientation to effect a setting of the combination of said service key. 

1. A key operated tumbler lock including provisions for changing the configuration of the service key usable to operate the lock and comprising: a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bores; a lock cylinder disposed for rotational motion within said cylinder bore and including a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores; a plurality of pin tumblers disposed in said lock body pin tumbler bores and said lock cylinder pin tumbler bores, at least one of said pin tumblers comprising a plurality of adjacent pin tumbler segments having adjacent surfaces with variable engagement characteristics dependent upon the relative orientation of said pin tumbler segments and changeable between at least a locking configuration and a passing configuration; means for placing said pin tumbler segments in said passing configuration to enable changing the configuration of the service key; and means for placing selected ones of said pin tumbler segments in said locking configuration to effect a change in the configuration of said service key.
 2. A key operated tumbler lock including provisions for changing the configuration of the service key and comprising: a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bore; a lock cylinder disposed for rotational motion within said cylinder bore and including a keyway and a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores; a plurality of pin tumblers disposed in said lock body pin tumbler bores and said lock cylinder pin tumbler bores, at least one of said pin tumblers comprising first and second adjacent pin tumbler segments, the adjacent surfaces of said first and second pin tumbler segments having variable engagement characteristics dependent upon the relative orientation of said first and second pin tumbler segments and changeable between at least a locking orientation and a passing orientation; means for placing said first and second pin tumbler segments in said passing orientation to enable changing the configuration of the service key; and means for selectively placing said first and second pin tumbler segments in said locking orientation to effect a change in the configuration of said service key.
 3. A key operated tumbler lock including provisions for changing the combination of the service key and comprising: a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bore; a lock cylinder disPosed for rotational movement within said cylinder bore and including a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores; a plurality of pin tumblers disposed in said pin tumbler bores, each pin tumbler comprising a plurality of adjacent locking pin tumbler segments, the interfacing surfaces of each adjacent pair of said locking pin tumbler segments having variable engagement characteristics dependent upon the relative orientation of the ones of said pair of adjacent locking pin tumbler segments and changeable between a locking orientation, a passover orientation, and a shear orientation; neutralizing means for orienting said locking pin tumbler segments so that each adjacent pair of said locking pin tumbler segments is in said shear orientation to enable changing the combination of the service key; and setting means for orienting said locking pin tumbler segments so that selected ones of said adjacent pairs of locking pin tumbler segments are in the locking orientation and other selected ones of said adjacent pairs of locking pin tumbler segments are in the passover orientation to effect a setting of the combination of said service key.
 4. A key operated tumbler lock including provisions for changing the combination of the service key and comprising: a lock body including a cylinder bore and a plurality of pin tumbler bores in communication with said cylinder bore; a lock cylinder disposed for rotational movement within said cylinder bore and including a plurality of pin tumbler bores corresponding to said lock body pin tumbler bores; a plurality of pin tumblers disposed in said pin tumbler bores, each pin tumbler comprising a plurality of adjacent locking pin tumbler segments, the interfacing surfaces of each adjacent pair of said locking pin tumbler segments having variable engagement characteristics dependent upon the relative orientation of the ones of said pair of adjacent locking pin tumbler segments and changeable between at least a locking orientation and a passing orientation; and means for orienting said locking pin tumbler segments so that selected ones of said adjacent pairs of locking pin tumbler segments are in the locking orientation and other selected ones of said adjacent pairs of locking pin tumbler segments as in the passing orientation to effect a setting of the combination of said service key. 